Introduction
The presented discussion of the structures of robot control systems is based on the concept of an agent. The agents having physical bodies (e.g., robots) are termed embodied agents. Both the operation of a single agent and the interactions between agents is of interest to us. The operation of an embodied agent is based on the concept of transition functions. The necessary concepts and an example of utilization of those concepts in the specification of a two-robot control system are presented in this paper. The example describes the specification and implementation of a haptic device. Haptic interfaces enable the human operator to acquire a remote sense of touch. The operator interacts with the master manipulator and through it commands the motion of the slave manipulator, but is also able to feel the forces of interaction between the slave and the environment. There are many research problems associated with haptic systems: the construction of the master [1, 4], haptic control [7, 6], stability of the haptic coupling [3]. Our implementation of the haptic system uses robot manipulators. Its formal specification is the subject of this part of the paper.